Is that understanding in error, or has the law been changed, thus allowing electronic distribution of W2's?
From the IRS website, as of January, 2013:
Furnishing Form W-2 to employees electronically. You may set up a
system to furnish Form W-2, Wage and Tax Statement, electronically.
Each employee participating must consent (either electronically or by
paper document) to receive his or her Form W-2 electronically, and you
must notify the employee of all hardware and software requirements to
receive the form. You may not send a Form W-2 electronically to any
employee who does not consent or who has revoked consent previously
provided.To furnish Forms W-2 electronically, you must meet the
following disclosure requirements and provide a clear and conspicuous
statement of each requirement to your employees.
The employee must be informed that he or she will receive a paper Form W-2 if consent is not given to receive it electronically.
The employee must be informed of the scope and duration of the consent.
The employee must be informed of any procedure for obtaining a paper copy of his or her Form W-2 and whether or not the request
for a paper statement is treated as a withdrawal of his or her
consent to receiving his or her Form W-2 electronically.
The employee must be notified about how to withdraw a consent and the effective date and manner by which the employer will confirm
the withdrawn consent. The employee must also be notified that the
withdrawn consent does not apply to the previously issued Forms W-2.
The employee must be informed about any conditions under which electronic Forms W-2 will no longer be furnished (for example,
termination of employment).
The employee must be informed of any procedures for updating his or her contact information that enables the employer to provide
electronic Forms W-2.
The employer must notify the employee of any changes to the employer's contact information.
You must furnish electronic Forms W-2 by the same due date as the paper Forms W-2. For more information on furnishing Form W-2 to employees electronically, see Regulations section 31.6051-1(j).
Section 31.6051-1(j) appears to be here if you are interested in some light reading. Search for "(j)" if you want to actually find the relevant section.
This is definitely legal, however, it appears employees must give consent for this to be acceptable for the IRS.
A disclaimer too: there is a mountain of paper and legal work related to this as you surely know. This is not intended to be legal advice of any sort.